Small parks could have a big role to play in the quest for bird conservation.
Though bird populations are in decline elsewhere, many bird species are stable or even growing at Lewis and Clark National Historical Park, according to a multiyear monitoring effort by The Institute for Bird Populations in partnership with the National Park Service and the U.S. Geological Survey.
While the message that bird populations are doing well is encouraging, even more exciting to researchers is the fact that birds are thriving in small, often less-protected parks.
Wilderness parks like Mount Rainier, North Cascades and Olympic — also included in monitoring efforts — can preserve old-growth forest and buffer birds from many human-related threats.
But researchers were curious to see what happened in smaller parks like Lewis and Clark and San Juan Island National Historical Park. These parks are more fragmented and more exposed to threats like pesticides and even domestic cats.
“The fact that these bird species have held their own or increased in these parks over the past decade suggests that these habitats are suitable for sustaining populations or are attracting birds from other areas,” said Chris Ray, an ecologist with The Institute for Bird Populations and lead author of the report.
“We definitely think these parks have value as habitat for species that are in decline elsewhere in the Pacific Northwest and across North America.”
“It’s good news,” said Chris Clatterbuck, chief of resource management at Lewis and Clark.
Bird populations are one of the National Park Service’s key vital signs, monitored as a way to determine the health of a park’s habitat.
“So just like a doctor would monitor blood pressure or your temperature, land bird populations are one of those things that we monitor,” Clatterbuck said.
Though several bird species were not doing as well and there are still serious questions about how climate change might impact even robust bird populations in the long term, researchers are encouraged by what they have seen over the years.
Lewis and Clark is home to estuaries and freshwater wetlands, as well as coastal and upland forests — habitats that are “locally rare,” according to the report. These pockets of unique habitat provide a sort of oasis to a variety of birds and are important to conserve certain bird populations.
“The different habitats attract a great mix of birds and we often find species in this park that we rarely see in the other areas we survey,” Mandy Holmgren, a biologist with The Institute for Bird Populations, who has monitored birds at Lewis and Clark, said in a statement.
So what’s next?
To Ray, some of the logical follow-up actions at Lewis and Clark would be to look at why some species — such as the small songbird Hutton’s vireo or the colorful Northern flicker, a member of the woodpecker family — are declining.
These birds seem to be experiencing a more general decline across the Pacific Northwest, Ray said, “and it is not yet clear whether these parks are providing suitable habitat for these species.”
Continued monitoring — and longer data sets — will also be necessary if the parks want to more clearly judge the effects of climate on bird populations.
Lewis and Clark rangers and volunteers participate in the Great Backyard Bird Count every year, hosting a range of activities, from birdwatching hikes to lectures, to get the public involved in spotting birds.
But few of the park’s restoration and habitat enhancement projects have been bird-centric, Clatterbuck said. Still, wetland restoration projects, primarily intended to help endangered salmon, end up benefiting a host of other species, including birds that feed or nest in wetland areas.
Recently, the park finished up thinning work as part of forest restoration and purposefully created snags — standing dead or dying trees — to enhance bird habitat.
“We’re hoping that will provide some good woodpecker habitat,” Clatterbuck said.
The park has also begun to track birds along its slice of the Pacific Flyway, a major migration route from Patagonia to Alaska. Millions of birds travel this route every year and Carla Cole, natural resource program manager at the park, hopes to capture them on sound recordings as they wing by.
Microphones, set up at two different locations at Lewis and Clark, are turned on during the spring migration. The Colorado State University Listening Lab later analyzes the audio files.
Sound recordings are a low-cost way for scientists to collect information about what species are present in an area. Cole was first inspired to experiment with bioacoustic monitoring after listening to an episode of "Science Friday," a weekly public radio show and podcast, in 2013.
She felt it could be an easy — and fascinating — way to detect species and measure the timing of the spring migration.
Several other national parks have since joined Lewis and Clark, but Cole hopes to get even more parks along the West Coast involved.
“Our primary research question is the timing of the spring migration, and how this may vary over time, particularly with climate change,” she said.